Improvement in blackboards



M. F. COWDERY.

Blackboard.

No.123,456. A PatentedFeb.,1a72.

MAROELLUS F. OOWDERY, OF SANDUSKY, OHIO.

IMPROVEMENT IN BLACKBOARDS. i

Specification forming part of Letters Patent No. 123,456, dated February 6, 1872.

consists in treating to a thorough coating of boiled oil the paper fabric which forms the body of the blackboard, to render the same impervious to moisture, and thereby prevent its warping or becoming harsh, and consequently cracking and becoming Worthless.

After the paper has been thus prepared I linish it on both sides With any of the ordinary blackboard compositions.

In the drawing, Figure l represents a blackboard, both sides of which are finished similarly; also, a section along the line X Y, in Whichb is the fabric, which has been treated with boiled oil, and c a are the coatings of blackboard compositions.

Having thus described my invention, what I claim as new, and desire to secure by Letters Patent, is-

The blackboard, When the paper fabric of which it is composed is previously treated with boiled oil, as and for the purposes herein described.

Witnesses: M. F. COWDERY.

M. E. McLoUTH, O. C. MGLOUTH. 

